592
ACUS01 KWNS 210054
SWODY1
SPC AC 210052
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0752 PM CDT THU AUG 20 2026
VALID 210100Z - 211200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF
THE UPPER MIDWEST TO THE CENTRAL PLAINS...THE SOUTHEAST AND MID
ATLANTIC TO THE SOUTHERN APPALACHIANS...
..SUMMARY
SCATTERED SEVERE STORMS REMAIN LIKELY THIS EVENING ACROSS PARTS OF
THE SOUTHERN MID ATLANTIC AND APPALACHIANS WITH A RISK FOR DAMAGING
WIND GUSTS AND A BRIEF TORNADO. LARGE HAIL AND ISOLATED DAMAGING
WINDS ARE EXPECTED WITH SEVERE STORMS FROM NEBRASKA INTO WISCONSIN
AND MINNESOTA. SCATTERED DAMAGING GUSTS ARE POSSIBLE OVER PARTS OF
THE DEEP SOUTH THIS EVENING.
..MID ATLANTIC INTO THE TN VALLEY AND THE CAROLINAS
EVENING WATER VAPOR IMAGERY SHOWED A SHORTWAVE TROUGH MOVING ACROSS
SOUTHERN PA AND THE DELMARVA TOWARD THE ATLANTIC COAST THIS EVENING.
NUMEROUS THUNDERSTORMS WERE ONGOING AHEAD OF THE UPPER WAVE NEAR A
FRONTAL ZONE FROM SOUTHERN NY AND PA SOUTHWARD INTO VA. AS THE WAVE
MOVES OFFSHORE THROUGH THE REMAINDER OF THIS EVENING, THE FRONT WILL
BEGIN TO SURGE EASTWARD WITH THE ASSOCIATED MOIST AND UNSTABLE AIR
MASS EVENTUALLY MOVING OFFSHORE WITH IT. DAMAGING GUSTS AND A BRIEF
TORNADO WILL REMAIN POSSIBLE WITH A MIX OF SUPERCELLS AND LINE
SEGMENTS AHEAD OF THE FRONT BEFORE MOVING OFFSHORE LATE THIS
EVENING.
FARTHER SOUTH, MORE ISOLATED CONVECTION REMAINS ONGOING ACROSS
SOUTHERN VA AND THE WESTERN CAROLINAS. DISPLACED FROM THE STRONGER
ASCENT OF THE PASSING SHORTWAVE TROUGH AND FLOW ALOFT, STORM
COVERAGE SHOULD REMAIN LOWER HERE. HOWEVER, MODERATE BUOYANCY AND
25-35 KT OF DEEP-LAYER SHEAR WILL SUPPORT SOME RISK FOR ORGANIZED
STORMS/CLUSTERS WITH DAMAGING GUSTS INTO THE EARLY OVERNIGHT HOURS
ACROSS EASTERN TN, NORTHERN AL AND THE WESTERN CAROLINAS.
..MIDWEST AND CENTRAL PLAINS
ISOLATED TO WIDELY SCATTERED STRONG/SEVERE THUNDERSTORMS HAVE
DEVELOPED AND SHOULD CONTINUE TO DO SO AHEAD OF A COLD FRONT AND
SURFACE TROUGH FROM NORTHERN MN, THE EASTERN DAKOTAS AND INTO NE
THIS EVENING. MODERATE TO LARGE BUOYANCY AND STRONG NORTHWESTERLY
FLOW WILL REMAIN FAVORABLE FOR ORGANIZED SUPERCELLS WITH HAIL AND
SEVERE GUSTS. AN ISOLATED TORNADO AND VERY LARGE HAIL ARE ALSO
POSSIBLE, PARTICULARLY FROM EASTERN SD INTO NE WHERE LOCALLY
STRONGER BUOYANCY MAY SUPPORT MAXIMUM DIAMETERS OF 2-3 INCHES.
SOME CLUSTERING AND A LOCAL INCREASE IN THE DAMAGING WIND RISK MAY
OCCUR ACROSS SOUTHERN NE AND NORTHERN KS THIS EVENING AS STORMS MOVE
NEARLY DUE SOUTH. VERY HOT SURFACE TEMPERATURES AND STEEP LAPSE
RATES IN LOW-LEVELS COULD SUPPORT FEW GUSTS OF 65-75+ MPH BEFORE
CONVECTION SLOWLY WEAKENS AFTER SUNSET.
..SOUTHEAST
SCATTERED THUNDERSTORMS ARE ONGOING AHEAD OF A WEAK COLD FRONT FROM
SOUTHEASTERN OK, INTO SOUTHERN AR AND LS/MS THIS EVENING. ADDITIONAL
SCATTERED STORMS WERE NOTED NEAR A WEAK MCV ALONG THE CENTRAL GULF
COAST. MODESTLY ENHANCED NORTHWESTERLY FLOW MAY MAINTAIN A FEW
STRONGER CLUSTERS THROUGH THIS EVENING WITHIN A WARM AND SEASONABLY
MOIST AIR MASS. WHILE MID-LEVEL LAPSE RATES ARE GENERALLY POOR,
2000-3000 J/KG OF MLCAPE AND PWATS OVER 2 INCHES WILL SUPPORT SOME
POTENTIAL FOR DAMAGING GUSTS WITH STRONGER DOWNDRAFTS AND STORM
CLUSTERS.
..AZ
BENEATH THE UPPER RIDGE, SCATTERED THUNDERSTORMS ARE ONGOING THIS
EVENING MOSTLY OVER THE HIGHER TERRAIN OF CENTRAL AZ. EXPECTATIONS
ARE FOR THESE STORMS TO PERSIST THIS EVENING OWING TO VERY HOT
SURFACE TEMPERATURES AND A SEASONABLY MOIST BOUNDARY LAYER. STEEP
LAPSE RATES AND INVERTED-V PROFILES WILL SUPPORT AN ISOLATED RISK
FOR SEVERE GUSTS WITH THE MORE INTENSE DOWNDRAFTS THIS EVENING.
..LYONS.. 08/21/2026
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